Wire locking structure for a filter device

ABSTRACT

This invention relates to a wire locking structure for a filter device, in which an outer circumference of a cylinder body is provided with a screw thread portion. The screw thread portion is wrapped by a wire of isosceles triangle in section. An end of the wire is drawn into a recess and firmly supported in a U-shape by an insert member to be inserted in the recess, thereby a conventional welding means has been removed.

BACKGROUND OF THE INVENTION

This invention relates to a wire locking structure for a filter device.

Referring to a filter device whose cylinder body is wrapped by a wire, both ends of the wire are fixed with an external circumference of the cylinder body by a conventional welding means.

However, the disadvantage of the conventional welding means is that the cylinder body and the wire may be deformed or deteriorated in quality due to high heating of welding. Further, there is the possibility that the wire may be extended due to thermal expansion, thereby a clearance gap between adjacent slits S may be deformed irregularly.

Still further, it is a cumbersome work to remove paddings in connection with welding.

BRIEF SUMMARY OF THE INVENTION

It is an object of this invention to provide a wire locking structure for a filter device, in which an end portion of the wire is drawn into a recess and firmly supported by an insert member to be inserted in the recess, thereby a conventional welding means has been removed.

Other and further objects, features and advantages of this invention will appear more fully from the following description in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIG. 1 is a partially cutaway front view of a filter device, in which a wire locking structure according to this invention is disposed.

FIG. 2 is a partially cutaway section view of a longitudinal passage, a wrapped wire and other components which are formed in the filter device in FIG. 1.

FIG. 3A is an exploded view of a wire locking structure for a filter device according to this invention.

FIG. 3B is a perspective view of the wire locking structure, in which an end portion of a wire is locked in a U-shape.

PREFERRED EXAMPLE OF THE INVENTION

A preferred example of this invention will be described with reference to the accompanying drawings.

Referring first to FIG. 1, a filter device F comprises a cylinder body 1 having a cavity 1a, a screw thread portion 2 formed on the outer circumference of the cylinder body 1, a plurality of longitudinal passages 4 formed on the outer circumference and spaced with each other and a plurality of lateral paths 5 spaced with each other and communicated with the cavity 1a and the plurality of longitudinal passages 4.

Numeral 6 is a metal wire of which the cross-section is an isosceles triangle. The wire 6 consists of a base a of length l, a bottom surface 6a and a summit b of height h. It is wrapped up between two flanks of the screw thread portion 2 in such a manner that the summit b of the wire 2 is fit in a screw bottom 2a thereof. Thus, a base portion of the wire 6 forms a nearly flattened surface of the cylinder body 1. Thus, a slit S is formed in a spiral form between adjacent wires 6 and a filter device F is formed.

FIGS. 3A and 3B respectively show an exploded view and a perspective view of a wire locking structure X for locking an end portion 6b of the wire 6 to be wrapped up round the outer circumference of the filter device F.

First of all, the end portion 6b of the wrapped wire 6 will be referred to. The end portion 6b thereof contacts a last corner 2b of the screw thread portion 2 and is disposed at the bottom of a recess 7. Numeral 8 is a half counter-sunk hole formed in the recess 7 and numeral 9 is a screwed portion formed at the end of the half counter-sunk hole 8.

Numeral 10 is an insert member which is, as shown in FIG. 3B, inserted into the recess 7. A top 10a of the insert member 10 forms a curved portion identical with an outer circumference of the cylinder body 1. The insert member 10 has a pair of cutaway portions 10f at both sides 10c, 10d, thereby a projecting portion 10b is formed. The projecting portion 10b is also cutaway at depth d so as to draw the wire 6 into the depth d portion. Further, the length l of the projecting portion 10b is equivalent to that of the wire 6. Thus, the cutaway portion 10f forms a U-shape. Still further, along a rear side 10g of the insert member 10 is formed a half counter sunk hole 11.

Numeral 12 is a locking bolt for fixing the insert member 10 with the wire 6 which is fit in the recess 7.

A process for locking the end portion 6b of the wire 6 will be described with reference to FIGS. 3A and 3B.

The end portion 6b of the wire 6 is drawn into the bottom of the recess 7 by way of the last corner 2b of the screw thread portion 2. Next to this, the insert member 10 is inserted into the recess 7 and the wire 6 is fit in the cutaway portion 10f of the insert member 10 in U-shape as shown in FIG. 3B.

Then, a right counter-sunk bolt is formed by combining the half counter-sunk hole 8 with the counter-sunk hole 11. Subsequently, the bolt 12 is screwed and firmly locked in the counter-sunk hole. Then, the summit b of the wire 6 is collapsed in the screw bottom 2a due to strong clamping. Accordingly, the wire 6 is fixed in the recess 7 more firmly. An edge of the end portion 6d is cut off so as to conform to the surface of the cylinder 1.

Thus, the wire locking structure X according to this invention is formed. As shown in FIG. 1, it is disposed at the beginning part of the wire 6 as well as at the last part thereof, namely at the upper side of the cylinder 1 as well as at the lower side thereof.

It is optional to form the recess 7 and the insert member 10 in a semicolumnar form.

Thus, the end portion of the wire is firmly supported in U-shape by the insert member, so that a width between adjacent slits is maintained uniformly. 

What is claimed is:
 1. A wire locking structure for a filter device, comprising:a cylinder body having a plurality of passages formed on an outer circumference thereof, said plurality of passages communicating with a cavity of said cylinder; a screw thread portion formed on said outer circumference containing screw bottoms; a wire having an isosceles triangle cross-section wrapped around said screw thread portion by inserting a summit of said wire in said screw bottoms; a recess to draw an end portion of said wire thereinto by way of a last corner of said screw thread portion, said recess including a half counter-sunk hole; an insert member inserted in said recess, said insert member including a half counter-sunk hole and a U-shaped cutaway portion for receiving said wire; and a locking bolt screwed and locked in a regular counter-sunk bolt formed by combining said half counter-sunk hole of said recess with said half counter-sunk hole of said insert member. 